Crayon World is a clean theme with a colorful header.

From the site:

Ambiru is a calm, reassuring theme developed for WordPress.

Ambiru is an unique single column theme with a header image.

Emire is a 2 column dark background theme.

From the site:

Emire is a theme which is just as comfortable in a commercial setting as it is on a personal site. Calm and aesthetically pleasing, Emire exudes an air of professionalism.

A dark background theme with green headers and photographic highlights.

From the site:

I designed Automatic Midnight to be a simple, flowing layout that was very minimal in color while showing nice contrast. It features a nice little tabbed comment system, automatic updates, is xhtml 1.0 Transitional compliant, css 2.0 compliant, and tableless. It’s a little different than most Wordpress themes as it adds some statistics such as post count, comment count, and lists the posts with most comments down the side.

An elegant design with a split sidebar.